There is proposed a sheet processing apparatus which performs post-processing such as folding processing to sheets printed by a printing apparatus (Japanese Patent Laid-Open No. 2006-193288).
According to this proposal, when folding sheets of different sizes, the user cannot determine the size of a sheet to be folded and that of a sheet not to be folded. The user cannot obtain an output result he wants.
The conventional sheet processing apparatus cannot process various types of jobs such as a job (to be referred to as a mixed size job) requiring sheets of different sizes in print processing of one set, and a job (to be referred to as an equal-size job) requiring sheets of the same size in print processing of one set.